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United States Patent | 5,707,441 |
Namikawa ,   et al. | January 13, 1998 |
In order to prepare a large yttrium or lanthanoid based oxide superconductor crystal of higher quality, a method and an apparatus which can stably control the shape of a pulled crystal and stably maintain growth of the crystal from a melt are provided. A crystal of an oxide having a structure of RBa.sub.2 Cu.sub.3 O.sub.7-X (R: yttrium or lanthanoid element, 0.ltoreq.X.ltoreq.1) is pulled from a raw material melt which is stored in a crucible by a rotary crystal pulling shaft. During such pulling, a position of the surface of the raw material melt is measured with time to obtain a lowering speed of the surface in a direction substantially parallel to the crystal pulling direction, for adjusting the lifting speed of the crystal pulling shaft by this lowering speed.
Inventors: | Namikawa; Yasuo (Tokyo, JP); Shiohara; Yuh (Tokyo, JP); Tanaka; Shoji (Tokyo, JP) |
Assignee: | Sumitomo Electric Industries, Ltd. (JP); International Superconductivity Technology Center (JP) |
Appl. No.: | 569895 |
Filed: | December 8, 1995 |
Dec 28, 1994[JP] | 6-327021 |
Current U.S. Class: | 117/14; 117/15; 117/201 |
Intern'l Class: | C30B 015/20 |
Field of Search: | 117/13,14,15,201,937 |
5240684 | Aug., 1993 | Baba et al. | 117/14. |
5485803 | Jan., 1996 | Habu | 117/14. |
Foreign Patent Documents | |||
0450502A1 | Oct., 1991 | JP | 117/14. |
K. Watanabe, "An approach to the growth of YBa.sub.2 Cu.sub.3 O.sub.7-x single crystals by the flux method. II", Journal of Crystal Growth, 1991, vol. 114, pp. 269-278. Elizabeth et al., "Growth and extraction of flux free YBCO crystals", Journal of Crystal Growth, 1992, vol. 121, pp. 531-535. Yamada et al., "Continuous Crystal Growth of Y123 by the Modified Top-Seeded Solution Growth" and related articles, 54th Oyo Butsuri Gakkai Gakujutsu Koenkai, 1993, 29-p-ZK-7. Yamada et al., "Continuous crystal growth of YBa.sub.2 Cu.sub.3 O.sub.7-x by the modified top-seeded crystal pulling method", Physica, C 217, 1993, pp. 182-188. Goriletsky et al., "Automated Pulling of Large Alkali Halide Single Crystals", Journal of Crystal Growth (1981) 509-513, from Proceedings of the Sixth International Conference on Crystal Growth, Moscow, USSR, Sep. 10-16, 1980. Eidelman et al., "Automated Growing of Large Single Crystals Controlled by Melt Level Sensor", Crystal Research and Technology vol. 20 No. 2 (1985) 167-172, East Germany. Sen et al., "Creep of CuO-BaO Melts Along the Container Wall", Materials Letters, vol. 7 No. 12 (Mar. 1989) 433-436. |